In the cancer treatment field, it is known that even if a primary carcinoma is treated by surgical resection, radiotherapy, chemotherapy or the like, cancer will recur at a certain rate. Further, it is known that many cases with recurrent cancer have a high degree of malignancy. Actually, the number of patients who will die due to cancer recurrence is higher than that of patients who will die due to the primary carcinoma. That is, the cancer recurrence is an important problem which determines a patient's prognosis. Hence, a process of judging a risk of cancer recurrence in patients whose primary carcinoma has been treated by surgery is very useful in determining a course of treatment after treatment as to the necessity of adjuvant chemotherapy.
Some factors for judging a risk of cancer recurrence are known in the art. Examples of the factors include age of patient, size of tumor, stage of progression, tumor tissue, nuclear grade classification, and presence of lymph node metastasis. Recently, many biomarkers according to the type of cancer have been identified. These biomarkers are used for the discovery of cancer and prognostic expectation. For example, as for breast cancer, hormone receptors such as estrogen receptors and receptor tyrosine kinases such as Her2 have attracted attention as biomarkers. Harbeck N. et al. have reported that a risk of breast cancer recurrence can be judged based on the expression levels of a urokinase plasminogen activator (uPA) and a plasminogen activator inhibitor 1 (PAI-1) (Harbeck N. et al., J. Clin. Oncol., vol. 20, No. 4, pp. 1000-1007 (2002) “Clinical Relevance of Invasion Factors Urokinase-Type Plasminogen Activator and Plasminogen Activator Inhibitor Type 1 for Individualized Therapy Decisions in Primary Breast Cancer Is Greatest When Used in Combination”).
The present inventors have disclosed methods of judging a degree of malignancy of cancer cells and a risk of cancer recurrence based on the expression levels and activity values of two types of cycline-dependent-kinases (CDK) (US2007/0231837 and US2009/0246809).